1. Field of the Invention
The present invention relates to semiconductor manufacturing systems, and more particularly to a control device employing a standardized communication input/output (I/O) interface between semiconductor production equipment and transport equipment.
2. Description of the Background Art
The Semiconductor Equipment and Material International (SEMI) has laid down international standards for the purposes of reducing time and cost and restricting personnel expenditure on equipment development and factory startup in the semiconductor manufacturing processes. Among them, there are SEMI E84 Specification for Enhanced Carrier Handoff Parallel I/O Interface for 300 mm wafer carriers, and SEMI E23-Specification for Cassette Transfer Parallel I/O Interface for 200 mm wafer carriers. The E84 specification is for handoffs (load/unload) of the 300 mm wafer carriers between production equipment load ports and automated material handling systems (AMHS).
In the E84 specification, an emergency stop (ES) signal is defined as follows. When the ES signal is off, it requires active equipment (the AMHS) to immediately stop the action. Passive equipment (semiconductor production equipment) turns off the ES signal in an emergency situation, i.e., when xe2x80x9chandoff interlock abnormalxe2x80x9d or the like has occurred and an ES button is depressed. The ES signal is employed solely for such specific applications. Other comparable signals have not been defined.
Referring to FIG. 1, a conventional system which brings the AMHS to an emergency stop by the ES signal based on SEMI E84 is described. As shown in FIG. 1, the system includes semiconductor production equipment 100, an AMHS 300 which grips a carrier 400 with a hand 330 to transport wafers to semiconductor production equipment 100, and an emergency stop button 128. In general, semiconductor production equipment 100 and AMHS 300 are manufactured by separate manufacturers and installed in a semiconductor manufacturing factory. Semiconductor production equipment 100 is provided with a controller (programmable controller, sequencer or the like) for control of semiconductor production equipment 100, and AMHS 300 is provided with a controller (programmable controller, sequencer or the like) for control of AMHS 300. Communication between the controller of semiconductor production equipment 100 and the controller of AMHS 300 is defined based on SEMI E84.
Emergency stop button 128 is depressed by an operator when an error has occurred in semiconductor production equipment 100 or an emergency stop of AMHS 300 is required. In response to the depression of emergency stop button 128, the controller of semiconductor production equipment 100 urgently stops semiconductor production equipment 100 itself, and also turns off the ES signal (which is on in a normal state). When the controller of AMHS 300 detects turning off of the ES signal, it stops the motion of AMHS 300.
As such, according to the conventional semiconductor manufacturing system, when emergency stop button 128 is depressed to bring AMHS 300 to an emergency stop, not only the movement of AMHS 300 but also the movement of semiconductor production equipment 100 would be stopped immediately, regardless of whether there is a problem in semiconductor production equipment 100. In such a case, processing on the wafers in progress in semiconductor production equipment 100 is suspended even if there is no error occurring in the device, which hinders shipping of the wafers as the finished products, thereby degrading the yield.
An object of the present invention is to provide, in a semiconductor manufacturing system designed based on SEMI E84, E23 or the like, a control device of the semiconductor manufacturing system for bringing active equipment to an emergency stop.
Another object of the present invention is to provide, in a semiconductor manufacturing system designed based on SEMI E84, E23 or the like, a control device of the semiconductor manufacturing system for bringing active equipment to an emergency stop with a simple configuration.
A further object of the present invention is to provide, in a semiconductor manufacturing system designed based on SEMI E84, E23 or the like, a control device of the semiconductor manufacturing system for bringing active equipment to an emergency stop to ensure safety of an operator.
A still further object of the present invention is to provide, in a semiconductor manufacturing system designed based on SEMI E84, E23 or the like, a control device of the semiconductor manufacturing system for facilitating recovery of active equipment from an emergency stop.
The control device according to the present invention controls a semiconductor manufacturing system including semiconductor production equipment and transport equipment transporting wafers contained in a carrier to the semiconductor production equipment. The semiconductor production equipment includes a first control circuit which has a circuit for bringing the semiconductor production equipment to an emergency stop. The transport equipment includes a second control circuit which has a circuit for bringing the transport equipment to an emergency stop. The first and second control circuits are connected by a signal line transmitting a signal which, when turned off, causes the second control circuit to bring the transport equipment to the emergency stop. The control device includes a receiving circuit which is connected to the first control circuit and receives an emergency stop signal for bringing the transport equipment to an emergency stop, and a control circuit which, in response to reception of the emergency stop signal, inhibits an output of emergency stop designation to the first control circuit and controls the signal on the signal line to turn off.
When the receiving circuit receives the emergency stop signal for bringing the transport equipment to an emergency stop, the control circuit turns off the signal being transmitted via the signal line connecting the first and second control circuits from the first control circuit to the second control circuit for bringing the transport equipment to an emergency stop. With this signal turned off, the second control circuit brings the transport equipment to an emergency stop. At this time, the output of the designation causing an emergency stop of the semiconductor production equipment to the first control circuit is inhibited. As such, on the occurrence of an error such as collision of the carrier transported by the transport equipment with the semiconductor production equipment, the transport equipment is brought to an emergency stop, whereas an undesired emergency stop of the semiconductor production equipment is prevented. As a result, it is possible to provide, in a semiconductor manufacturing system designed based on SEMI E84, E23 or the like, a control device of the semiconductor manufacturing system for bringing the transport equipment as the active equipment to an emergency stop.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.